Surface antigens of human glial brain tumor cells and VM murine spontaneous anaplastic astrocytoma cells were investigated by binding (indirect membrane immunofluorescence) and complement-dependent cytotoxic antibody (14C-nicotinamide release and dye-exclusion) assays. Antisera from nonhuman primates immunized with glioblastoma multiforme tissue or cells from permanent human glial brain tumor cell lines have been extensively absorbed to analyze which human glioma cell surface antigens may be species-, tissue-, or glial tumor-specific; oncofetal; or cross-reactive with non-glial tumor cell antigens. We have established an inbred colony of VM/dk mice, an in vivo transplantable VM astrocytoma line, and 3 VM astrocytoma cell lines. We will extend the initial finding of human glial tumor-associated antigenicity with additional primate antisera now in production and an expanded panel of neoplastic and non-neoplastic adult and fetal glial and non-glial human cell lines. Syn-, allo-, and xeno-geneic antisera raised against the VM astrocytoma will be analyzed for activity against murine oncornaviruses; antisera suitably absorbed will be analyzed for astrocytoma-associated antibody activity. In both systems we will extract from culture supernatants or cell membrane preparations antigenically active moieties by monitoring the process in inhibition assays with absorbed specific antisera. Radioimmunoprecipitation of labeled reactive antigenic moieties will be followed by polyacrylamide gel electrophoresis. Partial purification of solubilized antigens will be performed by gel filtration, ion exchange chromatography, and other gentle methods of protein separation. Specific antisera and solubilized antigen will be used to determine if body fluids of patients or cancerous mice contain glioma-distinctive antigens, measurement of which may serve diagnostic, disease process-monitoring, or immunotherapeutic purposes.